Laser Plate Welding with Opposite-Side Irradiation and Fillet Formation
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Solution Overview
Problem
Current laser welding methods face challenges such as narrow spot diameter requiring precise alignment, low precision leading to burn-through or insufficient penetration, difficulty in welding thick members, limited angular deformation control, need for additional equipment or processes for fillet formation, and limitations in welding complex shapes without sufficient strength.
Innovation Solution
A laser welding method that irradiates a laser beam onto the opposite surface of a metal plate to form a circular or oval weld with fillets, allowing for high positional tolerance and strength without filler metal, even in complex joints, by controlling the orbital scanning of the laser beam to ensure deep penetration and wide weld area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam with narrow spot diameter is used to achieve precise welding, then welding precision is improved, but positional tolerance decreases and alignment difficulty increases
Solution Approach 1:
The patent transitions from single-sided laser irradiation to dual-sided simultaneous irradiation, adding a spatial dimension to the welding process. This allows the laser beam to penetrate through the workpiece from both sides, creating a keyhole effect that maintains precise welding while tolerating greater positional variations in setup and alignment.
Solution Approach 2:
The patent changes the irradiation parameters by applying laser beams from both surface sides simultaneously onto positions counter to each other. This parameter change allows the narrow spot diameter to be maintained for precision while the dual-sided approach provides inherent tolerance to alignment errors through the keyhole penetration mechanism.
2Manufacturing precision
If groove butting precision is improved to avoid work gaps and burn-through, then welding quality is improved, but manufacturing cost increases significantly
Solution Approach 1:
By irradiating from both surface sides simultaneously, the patent creates a three-dimensional keyhole penetration effect that allows work gaps and imperfect groove butting to be bridged by molten metal flowing through the keyhole, eliminating the need for high-precision groove preparation.
Solution Approach 2:
The patent converts the previously harmful effect of work gaps and imperfect alignment into a beneficial feature by using dual-sided irradiation to create a keyhole that allows molten metal to flow and fill gaps, thereby tolerating lower manufacturing precision while maintaining weld quality.
3Strength
If laser welding is performed on thick members to achieve sufficient penetration depth, then welding capability is improved, but control difficulty increases due to burn-through or porosity at high energy density
Solution Approach 1:
The patent uses dual-sided simultaneous irradiation to create a keyhole penetration mode where the laser beams from opposite sides interact through the workpiece thickness. This allows controlled penetration through thick members by balancing the energy input from both sides, preventing excessive energy density that causes burn-through or porosity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances welding strength and productivity by reducing angular deformation, improving fatigue strength, and eliminating the need for additional equipment or processes, while maintaining high positional tolerance and avoiding burn-through.
Implementation Method 1
a laser beam irradiation step of irradiating a laser beam to the other main surface of the first member
Implementation Method 2
the first member and the second member are melted to form a weld portion
Data Source
AI summary
A laser welding method is a method for joining a first member in the shape of a plate and made of a metal material to a second member made of a metal material by laser welding. The laser welding method includes an arranging step and a laser beam irradiation step. In the arranging step, the second member is brought into contact with or brought close to one main surface of the first member. In the laser beam irradiation step, the other main surface of the first member is irradiated with the laser beam, the other surface being a main surface opposite to the one main surface of the first member. In the laser beam irradiation step, the first member and the second member are melted to form a weld portion having a substantially circular or oval shape in a plan view and to form a fillet on a joined portion between the first member and the second member.